Medical stapler and medical system

ABSTRACT

A medical stapler includes a grasping portion connected to an endoscope and having a first jaw and a second jaw connected by a rotation shaft; an operation portion configured to receive an external force for operating the grasping portion to open and close; a first wire configured to transmit the external force that is received by the operation portion to the grasping portion; and a movable pin attached to a distal end of the first wire, wherein the grasping portion is transitioned to an open state and a closed state by the first/second jaw relatively rotating with each other, and the movable pin is advanceable and retractable between positions at the proximal-end and distal-end side of the rotation shaft in a state in which the movable pin is engaged with an engagement groove formed in the first jaw.

The present application is a continuation application of PCTInternational Application No. PCT/JP2020/048476, filed on Dec. 24, 2020.The content of the above-identified PCT International Applications isincorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a medical stapler and a medicalsystem.

BACKGROUND ART

In recent years, the surgery to suture the gastrointestinal tract or thelike using a medical stapler is known. It is possible to facilitate theoperations to suture the gastrointestinal tract or the like andsignificantly shorten the operation period by using the suitable medicalstapler.

A full-thickness resection system disclosed in Published JapaneseTranslation No. 2004-503325 of the PCT International Publicationincludes an endoscope and a stapling mechanism arranged in thesurrounding of the endoscope. The full-thickness resection system isconfigured to observe the treatment target by the endoscope whileperforming the suturing treatment with respect to the treatment targetby the stapling mechanism.

SUMMARY

According to an aspect of the present disclosure, a medical stapler,includes a grasping portion connected to an endoscope and having a firstjaw and a second jaw connected by a rotation shaft; an operation portionconfigured to receive an external force for operating the graspingportion to open and close; a first wire including a proximal endconnected with the operation portion and a distal end connected with thegrasping portion and configured to transmit the external force that isreceived by the operation portion to the grasping portion; and a movablepin attached to the distal end of the first wire. The grasping portionis transitioned to an open state and a closed state by the first jaw andthe second jaw relatively rotating with the rotation shaft as a rotationcenter due to the external force transmitted by the first wire. Therotation shaft is positioned at a distal-end side of a distal end of theendoscope along a longitudinal direction of the endoscope. The movablepin is advanceable and retractable between a position at theproximal-end side of the rotation shaft and a position at the distal-endside of the rotation shaft along the longitudinal direction in a statein which the movable pin is engaged with an engagement groove formed inthe first jaw. A first tangent in a contact portion of the first jaw andthe movable pin and a second tangent in a contact portion of the secondjaw and the movable pin are inclined with each other at a slide angle θ,and the slide angle θ is determined by an equation, wherein the value μis a friction coefficient between the first jaw or the second jaw andthe movable pin.

tan θ>2*μ  (3)

According to another aspect of the present disclosure, a medical systemincludes an endoscope having flexibility; and a medical stapler engagedwith the endoscope, wherein the medical stapler includes a graspingportion connected to an endoscope and having a first jaw and a secondjaw connected by a rotation shaft; an operation portion configured toreceive an external force for operating the grasping portion to open andclose; a first wire including a proximal end connected with theoperation portion and a distal end connected with the grasping portionand configured to transmit the external force that is received by theoperation portion to the grasping portion; and a movable pin attached tothe distal end of the first wire. The grasping portion is transitionedto an open state and a closed state by the first jaw and the second jawrelatively rotating with the rotation shaft as a rotation center due tothe external force transmitted by the first wire. The rotation shaft ispositioned at a distal-end side of a distal end of the endoscope along alongitudinal direction of the endoscope. The movable pin is advanceableand retractable between a position at the proximal-end side of therotation shaft and a position at the distal-end side of the rotationshaft along the longitudinal direction in a state in which the movablepin is engaged with an engagement groove formed in the first jaw. Afirst tangent in a contact portion of the first jaw and the movable pinand a second tangent in a contact portion of the second jaw and themovable pin are inclined with each other at a slide angle θ, and theslide angle θ is determined by an equation, wherein the value U is afriction coefficient between the first jaw or the second jaw and themovable pin.

tan θ>2*μ  (3)

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a view showing a medical system including a medical stapleraccording to a first embodiment of the present disclosure.

FIG. 2 is a perspective view showing the medical stapler.

FIG. 3 is a front view showing a cap of the medical stapler.

FIG. 4 is a perspective view showing the medical stapler in which agrasping portion is in a closed state.

FIG. 5 is a front view showing the medical stapler in which the graspingportion is in the closed state.

FIG. 6 is a side view showing the medical stapler in which the graspingportion is in the closed state.

FIG. 7 is a perspective view showing the medical stapler in which thegrasping portion is in an open state.

FIG. 8 is a front view showing the medical stapler in which the graspingportion is in the open state.

FIG. 9 is a side view showing the medical stapler in which the graspingportion is in the open state.

FIG. 10 is a cross-sectional view showing the grasping portion includinga staple extraction portion.

FIG. 11 is a cross-sectional view showing the grasping portion in whichan extraction operation wire is pulled.

FIG. 12 is a view describing operations of the medical stapler.

FIG. 13 is a view describing the operations of the medical stapler.

FIG. 14 is a view describing the operations of the medical stapler.

FIG. 15 is a view describing the operations of the medical stapler.

FIG. 16 is a front view showing a medical stapler according to a secondembodiment of the present disclosure.

FIG. 17 is a side view in which a grasping portion of the medicalstapler according to the present embodiment is in a closed state.

FIG. 18 is a side view in which the grasping portion of the medicalstapler according to the present embodiment is in an open state.

FIG. 19 is a front view showing a cap of a medical stapler according toa third embodiment of the present disclosure.

FIG. 20 is a side view in which a grasping portion of the medicalstapler according to the present embodiment is in an open state.

FIG. 21 is a view describing operations of the medical stapler accordingto the present embodiment.

FIG. 22 is a cross-sectional view showing a grasping portion of amedical stapler according to a fourth embodiment of the presentdisclosure.

FIG. 23 is a side view in which the grasping portion of the medicalstapler according to the present embodiment is in a closed state.

FIG. 24 is a partial enlarged side view showing the grasping portion ofthe medical stapler according to the present embodiment.

FIG. 25 is a view showing a configuration in which a cap of the medicalstapler according to the present embodiment is attached to an endoscope.

DESCRIPTION OF EMBODIMENTS First Embodiment

A first embodiment of the present disclosure will be described referringfrom FIG. 1 to FIG. 15 .

FIG. 1 is a view showing an overall configuration of a medical system300 including a medical stapler 100 according to the present embodiment.

[Medical System 300]

The medical system 300 is used in the surgery for suturing thegastrointestinal tract or the like of a patient. As shown in FIG. 1 ,the medical system 300 includes the medical stapler 100, an endoscope200, an open-close operation portion (first operation portion) 250, anextraction operation portion (second operation portion) 270, and a wiresheath 280. The open-close operation portion 250 is an operation portionfor operating the medical stapler 100 by an open-close operation wire(first wire) 5. The extraction operation portion 270 is an operationportion for operating the medical stapler 100 by an extraction operationwire (second wire) 6.

[Endoscope 200]

As shown in FIG. 1 , the endoscope 200 includes an insertion portion210, an endoscope operation portion (third operation portion) 220, and auniversal cord 240. The insertion portion 210 is an elongated memberinserted into the body of the patient from a distal end thereof. Theendoscope operation portion 220 is provided at a proximal-end portion ofthe insertion portion 210. The endoscope 200 is suitably configuredusing a conventional flexible endoscope.

As shown in FIG. 1 , the insertion portion 210 is formed with atreatment device channel 230 through which the endoscopic treatmentdevice is inserted. At a distal end 212 of the insertion portion 210, aforceps port 214 as a distal-end opening of the treatment device channel230 is provided. The treatment device channel 230 extends from thedistal end 212 of the insertion portion 210 to the endoscope operationportion 220. The distal end 212 of the insertion portion 210 refers to aplane at the most distal-end side in a distal-end portion 211 of theinsertion portion 210 along the longitudinal direction of the endoscope200.

The distal-end portion 211 of the insertion portion 210 includes animaging unit (not shown) including an imaging element such as a CCD, aCMOS or the like and configured to acquire images or videos of thetreatment target T described below. An objective lens 215 of the imagingunit is exposed from the distal end 212 of the insertion portion 210.

At the proximal-end side of the endoscope operation portion 220, a knob223 for the surgeon to operate the insertion portion 210 and a switch224 for operating the imaging unit or the like are provided. The surgeoncan bend the insertion portion 210 to a desired direction by operatingthe knob 220.

At the distal-end side of the endoscope operation portion 220, a forcepsinsertion port 222 communicating with the treatment device 230 isprovided. The surgeon can insert the endoscopic treatment device intothe treatment device channel 230 from the forceps insertion port 222.

The universal cord 240 connects the endoscope operation portion 220 andexternal peripheral devices. For example, the universal cord 240 outputsthe images captured by the imaging unit to the external devices. Theimage captured by the imaging unit is displayed on a display device suchas an LCD display or the like.

[Open-Close Operation Portion 250]

The open-close operation portion (first operation portion) 250 is anoperation portion for the surgeon to open and close the medical stapler100 by operating the open-close operation wire (first wire) 5. As shownin FIG. 1 , the open-close operation portion 250 includes an open-closeoperation portion main body 252 and an open-close operation slider 253.The open-close operation slider 253 is connected with a proximal end ofthe open-close operation wire 5. The open-close operation wire 5 has therigidity for transmitting the force by the surgeon to press theopen-close operation slider 253 to the medical stapler 100 so as to openthe first grasping member (first jaw) 21 and the second grasping member(second jaw) 22. It is possible for the surgeon to advance and retractthe open-close operation wire 5 by advancing and retracting theopen-close operation slider 253 with respect to the open-close operationportion main body 252 along the longitudinal direction. Morespecifically, when the surgeon presses the open-close operation slider253, the open-close operation wire 5 advances into a predeterminedregion (first region) along the longitudinal direction and the medicalstapler 100 described below enters the open state. The first graspingmember 21 and the second grasping member 22 of the medical stapler 100relatively rotates with the open-close rotation shaft 23 as the rotationcenter such that the first grasping member 21 and the second graspingmember 22 are separated from each other and the medical stapler 100enters the open state. In the present embodiment, the open state of themedical stapler 100 includes a state in which the first grasping member21 and the second grasping member 22 are opened at substantially 90degrees, as shown in FIG. 7 .

When the surgeon pulls the open-close operation slider 253, theopen-close operation wire 5 retracts into the predetermined region(first region) along the longitudinal direction and the medical stapler100 are closed to enter the closed state. When the open-close operationwire 5 retracts along the longitudinal direction, the first graspingmember 21 and the second grasping member 22 relatively rotates with theopen-close rotation shaft 23 at the rotation center such that the firstgrasping member 21 and the second grasping member 22 approaches eachother and the medial stapler 100 enters the closed state. In the presentembodiment, the closed state of the medical stapler 100 refers to thestate in which the first grasping member 21 and the second graspingmember 22 included in the medical stapler 100 are opposite to each otherin the up-down direction B and to approach each other. The closed stateof the medical stapler 100 includes a state in which the first graspingmember 21 and the second grasping member 22 are opposite to each otherto be substantially parallel to each other and there is a gap formedtherebetween, as shown in FIG. 6 .

[Extraction Operation Portion 270]

The extraction operation portion (second operation portion) 270 is anoperation portion for the surgeon to extract the staple S from themedical stapler 100 by operating the extraction operation wire (secondwire) 6. As shown in FIG. 1 , the extraction operation portion 270includes an extraction operation portion main body 272 and an extractionoperation slider 273. A proximal end of the extraction operation wire 6is connected with the extraction operation slider 273. The surgeon canadvance and retract the extraction operation wire 6 in a predeterminedregion (second region) along the longitudinal direction by advancing andretracting the extraction operation slider 273 with respect to theextraction operation portion main body 272 along the longitudinaldirection. More specifically, in the present embodiment, when thesurgeon pulls the extraction operation slider 273, as described below,the extraction operation wire 6 retracts into the predetermined region(second region) along the longitudinal direction and the staple S isextracted from the accommodation space. Also, when the surgeon releasesthe operation of pulling the extraction operation slider 273, theextraction operation wire 6 may advance into the predetermined region(second region) along the longitudinal direction and the staple S may beaccommodated in a staple accommodation portion 31 (see FIG. 10 ).

[Wire Sheath 280]

The wire sheath 280 is a sheath through which the open-close operationwire 5 and the extraction operation wire 6 are inserted. As shown inFIG. 1 , the distal-end side of the wire sheath 280 is connected withthe insertion portion 210 of the endoscope 200 by a band 281. An exampleof the configuration in which the endoscope 200 and the band 281 areconnected with each other is shown in FIG. 25 . As shown in FIG. 25 ,the band 281 and the endoscope 200 are fixed therewith. On the otherhand, the wire sheath 280 formed in the material such as the resin orthe like is not fixed to the band 281. The wire sheath 280 is providedto be slidable along the longitudinal direction and movable with respectto the band 281. According to the present configuration, the wire sheath280 according to the present embodiment can slide following the bendingoperations of the endoscope 200.

[Medical Stapler 100]

FIG. 2 is a perspective view showing the medical stapler 100 accordingto the present embodiment.

The medical stapler 100 includes a cap 1, a grasping portion 2, a stapleextraction portion 3, a staple reception portion 4, the open-closeoperation wire 5, and the extraction operation wire 6. The medicalstapler 100 is attachable to and detachable from the distal end portion211 of the insertion portion 210.

FIG. 3 is a front view of the cap 1 viewed along the axial direction A.In FIG. 3 , the grasping portion 2 is transparently displayed.

The cap (attachment-detachment portion) 1 is a member that is attachableto the distal-end portion 211 of the endoscope 200. The cap 1 is formedin an approximately cylindrical shape, and the cap 1 has a firstpenetration hole 11 penetrating in the axial direction A and a secondpenetration hole 12 penetrating in the axial direction A.

The first penetration hole 11 is a hole in which the distal-end portion211 of the insertion portion 210 is inserted. The shape of the firstpenetration hole 11 is formed following the exterior shape of thedistal-end portion 211 of the insertion portion 210. Accordingly, thedistal-end portion 211 of the endoscope 200 is inserted into the firstpenetration hole 11 such that the cap 1 can be attached to thedistal-end portion 211 of the endoscope 200.

The central axis O1 of the first penetration hole 11 in the axialdirection A is eccentrical with respect to the central axis O of the cap1 in the axial direction A, as shown in FIG. 3 . The side in which thecentral axis O1 is eccentrical with respect to the central axis O isdefined as an “upper side B1”.

The second penetration hole 12 is a hole for the wire sheath 280 throughwhich the open-close operation wire 5 and the extraction operation wire6 are inserted to be inserted therein. An inner diameter of the secondpenetration hole 12 is approximately the same with the outer diameter ofthe wire sheath 280. The distal-end portion of the wire sheath 280 isinserted through the second penetration hole 12 to be fixed. Theopen-close operation wire 5 and the extraction operation wire 6inserting through the wire sheath 280 pass through the secondpenetration hole 12 to extend to the distal-end side.

As shown in FIG. 3 , the central axis O2 of the second penetration hole12 in the axial direction A is eccentrical with respect to the centralaxis O of the cap 1 in the axial direction A. The direction in which thecentral axis O2 is eccentrical with respect to the central axis O isopposite to the side (upper side B1) in which the central axis O1 iseccentrical with respect to the central axis O. The side in which thecentral axis O2 is eccentrical with respect to the central axis O isdefined as a “lower side B2”. In the present embodiment, the upper sideB1 and the lower side B2 are sides along the up-down direction B.

FIG. 4 , FIG. 5 , and FIG. 6 are a perspective view, a front view, and aside view of the medical stapler 100 in which the grasping portion 2 isin the closed state, respectively.

As shown in FIG. 4 , when the surgeon attaches the cap 1 to theendoscope 200, the medical stapler 100 is connected to the distal-endportion 211 of the insertion portion 210 of the endoscope 200 so as tobe attachable to and detachable from the distal-end portion 211. Whenthe cap 1 is attached to the distal-end portion 211 of the endoscope200, as shown in FIG. 4 and FIG. 5 , the objective lens 215 and theforceps port 214 are exposed from the opening 13 at the distal-end sidein the first penetration hole 11 of the cap 1. The surgeon can observethe treatment target T by the objective lens 215 even if the medicalstapler 100 is in the state of being attached to the distal-end portion211 of the endoscope 200.

The medical stapler 100 according to the present embodiment is notlimited to the configuration of using the cap 1 to be connected to theendoscope 200. It is possible to use variable conventionalconfigurations to connect the medical stapler 100 to the endoscope 200.For example, it is possible to use a rubber band to connect theproximal-end portion of the medical stapler 100 to the endoscope 200.For example, it is possible to form a screw hole in the distal-endportion 211 of the insertion portion 210 of the endoscope 200, and thenscrew a screw into the screw hole formed in the distal-end portion 211to attach and fix the medical stapler 100 to the distal-end portion 211of the insertion portion 210 of the endoscope 200. Furthermore, it ispossible to engage the medical stapler 100 and the endoscope 200 witheach other by forming a convex portion and a concave portion, a lockingmechanism or the like in the medical stapler 100 and the endoscope 200,respectively.

As shown in FIG. 5 , when the grasping portion 2 is in the closed state,the staple extraction portion 3 and the staple reception portion 4 areopposite to each other. When the grasping portion 2 is in the closedstate, a slightly narrow gap is formed between the staple extractionportion 3 and the staple reception portion 4. As shown in FIG. 4 , FIG.5 , and FIG. 6 , when the grasping portion 2 is in the closed state, theoptical axis A1 of the objective lens 215 is positioned at the upperside B1 with respect to the first grasping member 21 and the secondgrasping member 22. Also, when the grasping portion 2 is in the closedstate, the central axis A2 of the forceps port 214 does not overlap thefirst grasping member 21 in the front view; however, the central axis A2of the forceps port 214 is at the position overlapping the secondgrasping member 22.

As shown in FIG. 6 , the grasping portion 2 includes a first graspingmember (first jaw) 21, a second grasping member (second jaw) 22, anopen-close rotation shaft 23, and a movable pin 27. The first graspingmember 21 and the second grasping member 22 are connected by theopen-close rotation shaft 23 to be openable and closeable. In thepresent embodiment, the first grasping member 21 is configured to berotatable with respect to the second grasping member 22 with theopen-close rotation shaft 23 as the rotation center. The open-closerotation shaft 23 is provided at the distal-end side of the cap 1. Morespecifically, in the axial direction A, the open-close rotation shaft 23is provided at the distal-end side than the distal end 212 of theinsertion portion 210 of the endoscope 200. In FIG. 6 , the open-closerotation shaft 23 and the distal end 212 of the endoscope 200 areseparated from each other at a distance L1. The axial direction C of theopen-close rotation shaft 23 is orthogonal to the axial direction A ofthe cap 1 and the up-down direction B. As shown in FIG. 8 , the graspingportion 2 is symmetrically formed with respect to the central axis O3 inthe up-down direction B.

As shown in FIG. 6 , the first grasping member 21 includes a firstdistal-end portion 21 a and a first main body portion 21 b and is formedin a substantially T-shape in a planar view. The first distal-endportion 21 a is arranged at the distal-end side than the first main bodyportion 21 b.

The first distal-end portion 21 a is formed in a substantiallyrectangular parallelepiped shape. The first distal-end portion 21 a isformed in a rectangular shape extending in the axial direction C of theopen-close rotation shaft 23 in the planar view. The first distal-endportion 21 a is provided with the staple extraction portion 3. Theopening 31 a of the staple extraction portion 3 is provided on thesurface (upper surface 21 e) at the upper side B1 of the firstdistal-end portion 21 a.

The first main body portion 21 b is an elongated member extending in theaxial direction A. The distal end of the first main body portion 21 b isfixed to the first distal-end portion 21 a. The proximal end of thefirst main body portion 21 b is fixed to the cap 1. The first main bodyportion 21 b includes a contact pin 21 c and a first engagement groove21 d.

The contact pin 21 c is provided at the proximal end of the first mainbody portion 21 b, and the contact pin 21 c is configured to come intocontact with the second grasping member 22 in the closed state toregulate the moveable range of the second grasping member 22. Morespecifically, according to the present embodiment, when the graspingportion 2 is in the closed state, the distal-end portion of the firstgrasping member 21 and the distal-end portion of the second graspingmember 22 are separated from each other by a predetermined distance ormore. In other words, when the grasping portion 2 is in the closedstate, a gap equal to or more than the predetermined distance is formedbetween the distal-end portion of the first grasping member 21 and thedistal-end portion of the second grasping member 22. As described below,when the grasping portion 2 enters the closed state, the living tissuesas the treatment target T is clamped between the first grasping member21 and the second grasping member 22. Accordingly, if the gap formed inthe grasping portion is too small, the crushing due to the grasping andthe ischemia after the stapling may occur. Accordingly, in the presentembodiment, the distance of the gap formed in the grasping portion 2 inthe closed state is limited to be equal to or larger than thepredetermined value by providing the contact pin 21 c. In the presentembodiment, the distance of the gap formed in the grasping portion 2 inthe closed state may be appropriately determined by taking the type ofthe treatment target into consideration.

As shown in FIG. 6 , the first engagement groove 21 d is a groovepenetrating in the axial direction C of the open-close rotation shaft 23in the first main body portion 21 b. The first engagement groove 21 dextends in the axial direction A.

The second grasping member 22 is attached to the first grasping member21 by the open-close rotation shaft 23 to be rotatable. The secondgrasping member 22 includes a U-shaped member 22 a formed in asubstantially U shape, and a second main body portion 22 b rotatablysupporting the U-shaped member 22 a.

The U-shaped member 22 a is formed in the substantially U-shape, whereintwo end portions thereof are connected with the second main body portion22 b, and a central portion is arranged at the distal-end side. Thecentral portion includes the second distal-end portion 22 c. The seconddistal-end portion 22 c is formed in the substantially rectangularparallelepiped shape. The second distal-end portion 22 c is providedwith the staple reception portion 4.

The second main body portion 22 b is rotatably attached to the firstmain body portion 21 b of the first grasping member 21 by the open-closerotation shaft 23. A guide groove 22 d into which the first main bodyportion 21 b is inserted is formed in the second main body portion 22 b.The second engagement grooves 22 e are formed in the two side portionsof the guide groove 22 d of the second main body portion 22 b.

The second engagement groove 22 e is a groove formed in the second mainbody portion 22 b. The second engagement groove 22 e is the groovepenetrating in the axial direction C. In the side view, the secondengagement groove 22 e is formed at the opposite side of the staplereception portion 4 to sandwich the open-close rotation shaft 23therebetween. The second engagement groove 22 e is symmetrical withrespect to the central axis O3 of the second grasping member 22.

As shown in FIG. 7 , the first grasping member 21 is fixed to thedistal-end side of the cap 1 to not be rotatable. The first graspingmember 21 is fixed to the cap 1 at the lower side B2 with respect to thecentral axis O of the cap 1. As shown in FIG. 3 , the first graspingmember 21 is arranged at a position overlapping the second penetrationhole 12 in the front view. On the other hand, as shown in FIG. 8 , thefirst grasping member 21 is arranged at the position not to overlap theobjective lens 215 and the forceps port 214 of the endoscope 200 in thefront view.

As shown in FIG. 8 , the second grasping member 22 includes thevisual-field space 25 penetrating in the open-close direction R betweenthe staple reception portion 4 at the distal-end side and the open-closerotation shaft 23 at the proximal-end side. In the present embodiment,the visual-field space 25 is the space being surrounded by the sides ofthe U-shaped member 22 a formed in the substantially U-shape. In otherwords, in the front view shown in FIG. 8 , when the grasping portion 2enters the open state, the objective lens 215 and the forceps port 214of the endoscope 200 are exposed to the visual-field space 25 formed inthe U-shaped member 22 a of the second grasping member 22 describedbelow.

In the present embodiment, the position of the open-close rotation shaft23 in the front view shown in FIG. 8 , the position of the objectivelens 215 provided in the endoscope 200 connected with the cap 1, and theposition of the forceps insertion port 222 formed in the endoscope 200satisfy a predetermined positional relationship. As shown in FIG. 8 , adistance (first distance) between the central axis O4 of the endoscope200 and the open-close rotation shaft 23 in the up-down direction B isdefined as the distance L_(S), a distance (second distance) between thecentral axis O4 of the endoscope 200 and the central axis of theobjective lens 215 is defined as the distance L_(CL), and a radius of acircle with the central axis O4 of the endoscope 200 as the center thatcircumscribes the forceps insertion port 222 is defined as the radiusR_(F). In the present embodiment, the distance L_(S) between the centralaxis O4 of the endoscope 200 and the open-close rotation shaft 23 isequal to or larger than the radius R_(F). The distance L_(S) between thecentral axis O4 of the endoscope 200 and the open-close rotation shaft23 is equal to or larger than the distance L_(CL) between the centralaxis O4 of the endoscope 200 and the central axis of the objective lens215.

According to the present embodiment, the distance L_(S) between thecentral axis O4 of the endoscope 200 and the open-close rotation shaft23 is equal to or larger than the radius R_(F) such that it is possibleto avoid the interference between the grasping portion 2 and variousendoscopic treatment devices inserted through the forceps insertion port222 including the grasping forceps G described below. In other words,with respect to the grasping portion 2 in the open state or the closedstate, it is possible to advance and retract the endoscopic treatmentdevices inserted through the forceps insertion port 222 to perform thetreatment with respect to the treatment target T.

According to the present embodiment, the distance L_(S) between thecentral axis O4 of the endoscope 200 and the open-close rotation shaft23 is equal to or larger than the distance L_(CL) between the centralaxis O4 of the endoscope 200 and the central axis of the objective lens215 such that when the various endoscopic treatment devices are insertedthrough the forceps insertion port 222 to be operated to advance andretract, it is possible to prevent the visual field of the objectivelens 215 for observing the treatment target T from being cut off.

As shown in FIG. 6 , the movable pin 27 is engaged in the firstengagement groove 21 d and the second engagement groove 22 e, and ismovable in the axial direction A along the first engagement groove 21 d.The distal end of the open-close operation wire 5 is attached to themovable pin 27. As shown in FIG. 9 , when the movable pin 27 advancestoward the distal-end side together with the open-close operation wire 5by the operations of the surgeon, the second grasping member 22 rotateswith respect to the first grasping member 21 with the open-closerotation shaft 23 as the center such that the grasping portion 2 entersthe open state. At this time, the first grasping member 21 and thesecond grasping member 22 form an angle of substantially 90 degrees.That is, the first grasping member 21 and the second grasping member 22are substantially orthogonal to each other. On the other hand, when themovable pin 27 retracts to the proximal-end side together with theopen-close operation wire by the operations of the surgeon, as shown inFIG. 6 , the second grasping member 22 rotates with respect to the firstgrasping member 21 with the open-close rotation shaft 23 as the centersuch that the grasping portion 2 enters the closed state. As shown inFIG. 6 and FIG. 9 , when the movable pin 27 advances from the positionat the proximal-end side than the open-close rotation shaft 23 to thedistal-end side of the endoscope 200 along the axial direction A, thegrasping portion 2 transitions from the closed state to the open state.On the other hand, when the movable pin 27 retracts from the position atthe distal-end side than the open-close rotation shaft 23 to theproximal-end side of the endoscope 200, the grasping portion 2transitions from the open state to the closed state. It is preferablethat the movable pin 27 is aligned with the surfaces of the firstgrasping member 21 and the second grasping member 22 in the axialdirection C or slightly pop out from the surfaces of the first graspingmember 21 and the second grasping member 22 in the axial direction C.

As shown in FIG. 9 , when the grasping member 2 is in the open state,the staple reception portion 4 is disposed at the proximal-end side thanthe open-close rotation shaft 23. As shown in FIG. 6 , FIG. 7 , and FIG.9 , when the grasping portion 2 is in the open state, the stapleextraction portion 3 and the staple reception portion 4 are arranged attwo sides of the optical axis A1 of the objective lens 215 to sandwichthe optical axis A1 of the objective lens 215. When the grasping portion2 is in the open state, the optical axis A1 of the objective lens 215passes through the visual-field space 25. Also, when the graspingportion 2 is in the open state, the central axis A2 of the forceps port214 passes through the visual-field space 25.

FIG. 10 is a cross-sectional view showing the grasping portion 2including the staple extraction portion 3.

The staple extraction portion 2 is arranged in the first distal-endportion 21 a of the first grasping member 21 and configured toaccommodate and extract the staples S. The staple extraction portion 3includes a staple accommodation portion 31, a straight-moving member 32,and a rotation member 33.

The staple accommodation portion 31 is the space provided in the firstdistal-end portion 21 a of the first grasping member 21 foraccommodating the staples S. As shown in FIG. 7 , two of the stapleaccommodation portions 31 are formed side by side in the axial directionC in the first grasping member 21 so as to be able to accommodate two ofthe U-shaped staples S.

The staple accommodation portion 31 has the opening 31 a provided on theupper surface 21 e of the first distal-end portion 21 a to open in theup-down direction B. The staples S are accommodated in the stapleaccommodation portion 31 from the opening 31 a. The staples S areaccommodated in the staple accommodation portion 31 in the state inwhich the needle tip S1 of the staple S is directed toward the upperside B1.

In the planar view, the staple accommodation portion 31 is formed in arectangular shape that the short side extends in the axial direction Aand the long side extends in the axial direction C. The staples Saccommodated in the staple accommodation portion 31 are arranged thatthe needle tips S1 at two ends thereof are arrayed in the axialdirection C.

The straight-moving member 32 is the member accommodated in the stapleaccommodation portion 31 and movable in the inside space of the stapleaccommodation portion 31 along the up-down direction B. Thestraight-moving member 32 includes the concave portion 32 a at the upperside B1 to support the staple S. The staple S accommodated in the stapleaccommodation portion 31 is fitted into the concave portion 32 a.

A first pulley 34 and a second pulley 36 as the rotation member 33 areattached to the inside of the first grasping member 21 to be rotatable,and the first pulley 34 and the second pulley 36 rotate so as to movethe straight-moving member 32 in the up-down direction B. The distal-endof the extraction operation wire 6 is connected to the first pulley 34.It is possible to rotate the first pulley 34 by pulling the extractionoperation wire 6.

The second pulley 36 is attached to the inside of the first graspingmember 21 to be rotatable, and the first pulley 34 is disposed at thedistal-end side of the second pulley 35. The rotation axis 35 of thefirst pulley 34 and the rotation axis 37 of the second pulley 36 extendin the axial direction C and substantially parallel to the open-closeshaft 23 of the grasping portion 2. The first pulley 34 includes theconvex portion (contact portion) 38 at the distal-end side to supportthe straight-moving member 32 from the lower side B2.

The distal end of the extraction operation wire 6 is connected to thefirst pulley 34 at the position at the upper side B1 than the rotationaxis 35. The extraction operation wire 6 passes through the secondpenetration hole 12 from the first pulley 34 via the second pulley 36 toextend to the extraction operation portion 270. The reason for providingthe second pulley 36 is to suitably perform the position adjustment forguiding the extraction operation wire 6 to the second penetration hole12 and reduce the friction resistance at the time of guiding theextraction operation wire 6 to the second penetration hole 12.Accordingly, the same effect can be achieved by using the first pulley34 only as the rotation member 33 and providing a member(friction-reduction member) in an R-shape and with a suitableslidability instead of the second pulley 36.

FIG. 11 is a cross-sectional view showing the grasping portion 2 inwhich the extraction operation wire 6 is pulled.

By pulling the extraction operation wire 6, the portion at theupper-side B1 of the first pulley 34 rotates to the proximal-end side,and the portion at the lower-side B2 of the first pulley 34 rotates tothe distal-end side. As a result, the convex portion 38 of the firstpulley 34 pushes up the straight-moving member 32 to the upper-side B1to extract the accommodated staple S to the upper-side b1 from theopening 31 a.

The staple reception portion 4 is provided on the lower surface 22 f ofthe second distal-end portion 22 c of the second grasping member 22. Thestaple reception portion 4 is provided with a plurality of pockets 41being capable of accommodating the staples extracted from the stapleextraction portion 3. In the present embodiment, two of the U-shapedstaples are extracted from the staple extraction portion 3 such thatthere are four pockets 41 are provided in the staple reception portion4. As shown in FIG. 10 , when the grasping portion 2 is in the closedstate, the opening 31 a from which the staple S is extracted and thepocket 41 of the staple extraction portion 3 are opposite to each other.

As shown in FIG. 10 and FIG. 11 , in the medical stapler 100 accordingto the present embodiment, the extraction operation wire 6 is disposedto be closer to the open-close rotation shaft 23 side than theopen-close operation wire 5. In other words, in the medical stapler 100,the extraction operation wire 6 is positioned at the upper side of thecap 1 than the open-close operation wire 5. The medical stapler 100 hassuch a configuration such that the staple accommodation portion 31, thestraight-moving member 32, and the rotation member 33 included in thestaple extraction portion 3 can be arranged to avoid the movable rangeof the movable pin 27, that is, the range in which the first engagementgroove 21 d is formed. In other words, the open-close operation wire 5and the extraction operation wire 6 are arranged in this configurationsuch that the staple accommodation portion 31, the straight-movingmember 32, and the rotation member 33 are arranged at the lower side B2of the medical stapler 100 or at the distal-end side in the axialdirection A so as to avoid the upsizing of the staple extraction portion3.

[Operations of Medical Stapler 100]

Next, the operations of the medical stapler 100 will be described. FIG.12 to FIG. 15 are views for describing the operations of the medicalstapler 100.

The surgeon moves the distal-end portion 211 of the endoscope 200 towhich the medical stapler 100 is attached to approach the treatmenttarget T. The surgeon operates the open-close operation portion 250 toadvance the open-close operation wire 5 to make the grasping portion 2into the open state. The optical axis A1 of the objective lens 215passes through the visual-field space 25 such that the surgeon canobserve the treatment target T through the imaging unit of the endoscope200. Also, the central axis A2 of the forceps port 214 passes throughthe visual-field space 25 such that as shown in FIG. 12 , the surgeoncan protrude the grasping forceps G from the forceps port 214 to performthe treatment with respect to the treatment target T.

As shown in FIG. 13 , the surgeon retracts the grasping forceps C in thestate of grasping the treatment target T by the grasping forceps G. Thesurgeon retracts the grasping forceps G so as to dispose the distal endof the grasping forceps G at the proximal-end side than the stapleextraction portion 3.

As shown in FIG. 14 , the surgeon operates the open-close operationportion 250 to retract the open-close operation wire 5 to cause thegrasping portion 2 in the closed state. The treatment target T isclamped by the staple extraction portion 3 of the first grasping member21 and the staple reception portion 4 of the second grasping member 22.

When the grasping portion 2 is in the closed state, part of thetreatment target T that is clamped by the grasping forceps G can beaccommodated in the space (visual-field space 25) formed by the U-shapedmember 22 a and the second main body portion 22 b of the second graspingmember 22 such that it is difficult for the treatment target T that isclamped by the staple extraction portion 3 and the staple receptionportion 4 to escape.

As shown in FIG. 8 , when the grasping portion 2 is in the closed state,the optical axis A1 of the objective lens 215 passes through the outsideof the first grasping member 21 and the second grasping member 22.Accordingly, it is also possible for the surgeon to observe thetreatment target T through the imaging unit of the endoscope 200 evenwhen the grasping portion 2 is in the closed state.

The surgeon operates the extraction operation portion 270 to pull theextraction operation wire 6 in the state in which the treatment target Tis clamped by the staple extraction portion 3 and the staple receptionportion 4 to extract the accommodated staples S toward the staplereception portion 4. The needle tips S1 of the staple S penetrate thetreatment target T to come into contact with the pocket 41 of the staplereception portion 4 to be bent. As a result, the treatment target T issutured.

As shown in FIG. 15 , the surgeon operates the open-close operationportion 250 to make the grasping portion 2 into the open state again.The surgeon separates the grasping forceps G from the treatment target Tto finish the suturing treatment.

According to the medical stapler 100 disclosed in the presentembodiment, the insertion diameter of the medical stapler 100 in whichthe grasping portion 2 is in the closed state is substantially the samewith that of the distal-end portion 211 of the endoscope 200 such thatit is easy to be inserted into the body such as the gastrointestinaltract or the like. Also, even the grasping portion 2 of the medicalstapler 100 is in the open state, the surgeon can observe the treatmenttarget T via the imaging unit of the endoscope 200 and protrude thegrasping forceps C from the forceps port 214 to perform the treatmentwith respect to the treatment target T.

According to the medical stapler 100 disclosed in the presentembodiment, the open-close rotation shaft 23 is disposed at thedistal-end side of the distal end 212 of the endoscope 200. According tothe configuration, the outer diameter in the radial direction of themedical stapler 100 is formed to be thinner as compared with the staplerconfigured to cover the endoscope that is disclosed in the conventionaltechnology. As a result, even in a narrow surgery site such as thegastrointestinal tract or the like in the body of the patient, it ispossible to smoothly switch the open state and the closed state of thegrasping portion 2 of the medical stapler 100.

According to the medical stapler 100 disclosed in the presentembodiment, the position of the open-close rotation shaft 23, theposition of the objective lens 215 provided in the endoscope 200, andthe position of the forceps insertion port 222 satisfy the predeterminedpositional relationship. Accordingly, the opening operation and theclosing operation of the grasping portion 2 of the medical stapler 100and the operations to introduce the endoscopic treatment device via theforceps insertion port 222 do not interfere with each other. It ispossible to prevent the visual field of the objective lens 215 of theendoscope 200 from being cut off by the opening operation and theclosing operation of the grasping portion 2 of the medical stapler 100.

According to the medical stapler 100 disclosed in the presentembodiment, the extraction operation wire 6 is disposed to be closer tothe open-close rotation shaft 23 side than the open-close operation wire5. Accordingly, it is possible to realize the miniaturization of themedical stapler 100.

According to the medical stapler 100 disclosed in the presentembodiment, when the grasping portion 2 is in the open state, the secondgrasping member 22 is positioned between the open-close rotation shaft23 and the endoscope 200 in the axial direction A. Accordingly, it ispossible to prevent the second grasping member 22 from entering thevisual field of the objective lens 215 provided in the endoscope 200.

According to the medical stapler 100 disclosed in the presentembodiment, the movable pin 27 advances and retracts in the state ofengaging with the first engagement groove 21 d together with theadvancement and the retraction of the open-close operation wire 5.Accordingly, it is possible for the surgeon to operate the open-closeoperation wire 5 with a relatively small force so as to make thegrasping portion 2 to transition to the open state and the closed state.The movable pin 27 is provided to be freely advanceable and retractablealong the longitudinal direction of the endoscope 200 between theposition at the proximal-end side of the open-close rotation shaft 23and the positon at the distal-end side of the open-close rotation shaft23 in the state of engaging with the first engagement groove 21 d of thefirst grasping member 21. According to the configuration, the medicalstapler 100 according to the present embodiment is formed as the smallmechanism and when the grasping portion 2 is in the open state, theopening angle between the first grasping member 21 and the secondgrasping member 22 is large.

As described above, the first embodiment of the present disclosure hasbeen described in detail with reference to the drawings, however, thespecific configuration is not limited to the present embodiment, anddesign changes and the like are included within the scope of the presentinvention. Also, the configuration elements shown in the above-describedembodiment and modification examples can be combined as appropriate.

Second Embodiment

Hereinafter, a medical stapler 100A according to a second embodiment ofthe present disclosure will be described by referring to FIG. 16 to FIG.18 . In the following description, the common configuration that havebeen described will be designated with the same reference signs and theduplicate description will be omitted.

FIG. 16 is a front view showing a grasping portion 2A of the medicalstapler 100A in the open state according to the present embodiment. FIG.17 is a side view showing the grasping portion 2A in the closed state.FIG. 18 is a side view showing the grasping portion 2A in the openstate.

As shown in FIG. 16 , as compared with the grasping portion 2 of themedical stapler 100 according to the first embodiment, the graspingportion 2A of the medical stapler 100A in the open state according tothe present embodiment includes a second grasping member 22A in which alarger visual-field space 25A is formed therein. As shown in FIG. 17 ,in the medial stapler 100A according to the present embodiment, athickness D in the up-down direction B of the second grasping member 22Ain the closed state is larger than the thickness of the second graspingmember 22 of the medical stapler 100 according to the first embodiment.As shown in FIG. 17 , the distance L2 between the open-close rotationshaft 23A of the medical stapler 100A and the distal end 212 of theendoscope 200 is smaller than the distance L1 in the medical stapler 100according to the first embodiment.

According to the present embodiment, when the grasping portion 2A is inthe open state, the outer diameter of the distal-end portion of the cap1A is smaller than that according to the first embodiment such that thesecond grasping member 22A does not collide with the cap 1A. The medicalstapler 100A according to the present embodiment has the above-describedconfiguration such that when the grasping portion 2A enters the openstate, as shown in FIG. 16 , the second grasping member 22A of thegrasping portion 2A in the open state is positioned at the outside inthe radial direction with respect to the endoscope 200 in the frontview. Also, as shown in FIG. 18 , the second grasping member 22A isarranged to overlap part of the distal-end portion 211 of the endoscope200 and the cap 1A.

The other configurations of the medical stapler 100A according to thepresent embodiment are the same with that of the medical stapler 100according to the above-described first embodiment. For example, as shownin FIG. 17 and FIG. 18 , the open-close rotation shaft 23A is positionedat the distal-end side of the distal end 212 of the endoscope 200. Forexample, in the front view shown in FIG. 16 , the position of theopen-close rotation shaft 23A, the position of the objective lens 215provided in the endoscope 200 connected with the cap 1, and the positonof the forceps insertion port 222 formed in the endoscope 200 satisfythe predetermined positional relationship disclosed in the firstembodiment.

According to the medical stapler 100A disclosed in the presentembodiment, when the grasping portion 2A enters the open state, thesecond grasping member 22A is positioned at the outside in the radialdirection than the endoscope 200 such that the outer diameter thereof islarger than that of the medical stapler 100 according to the firstembodiment. However, compared with the configuration disclosed in theconventional technology, the insertion diameter of the medical stapler100A is sufficiently small. Accordingly, according to the medicalstapler 100A disclosed in the present embodiment, similar to the medicalstapler 100 according to the first embodiment, it is possible to performthe treatment on the treatment target T even in the narrow surgery siteby transitioning the grasping portion 2 to the open state and the closedstate. According to the medical stapler 100A disclosed in the presentembodiment, it is possible to realize the treatment with respect to thetreatment target T by using a thicker second grasping member and thetreatment with respect to the treatment target T by using the medicalstapler having a shorter length in the axial direction A.

Third Embodiment

Hereinafter, a medical stapler 100B according to a third embodiment ofthe present disclosure will be described by referring to FIG. 19 to FIG.21 . The medical stapler 100B according to the present embodiment isdifferent from the medical stapler 100 according to the above-describedfirst embodiment in the opening direction of the grasping portion in theopen state.

FIG. 19 is a front view when the grasping portion 2B of the medicalstapler 100B according to the present embodiment is in the closed state.FIG. 20 is a side view when the grasping portion 2B of the medicalstapler 100B according to the present embodiment is in the open state.FIG. 21 is a view for describing the operation of the treatment usingthe medical stapler 100B.

As shown in FIG. 19 , in the medical stapler 100B according to thepresent embodiment, the second grasping member 22B of the graspingportion 2B is arranged at the outside than the first grasping member 21Bin the radial direction of the medical stapler 100B. As shown in FIG. 20, with respect to the medical stapler 100B, when the surgeon presses theopen-close operation wire 5, the second grasping member 22B rotates withrespect to the first grasping member 21B such that the grasping portionenters the open state. At this time, the grasping portion 2B in the openstate opens toward the lower side B2 of the endoscope 200. The otherconfigurations of the medical stapler 100B according to the presentembodiment are the same with that of the medical stapler 100 accordingto the above-described medical stapler 100.

As shown in FIG. 21 , at the time of using the medical stapler 100Baccording to the present embodiment to perform the treatment withrespect to the treatment target T, the visual field of the objectivelens 215 of the endoscope 200 is cut off by the grasping portion 2B.That is, it is impossible for the surgeon to acquire the images or thelike of the treatment target T by using the objective lens 215 of theendoscope 200. However, in a case in which the dimension of thetreatment target T is small, it is possible for the surgeon to directlytransition the grasping portion 2B to the closed state to perform thetreatment with respect to the treatment target T without confirming theimages of the treatment target T.

According to the medical stapler 100B disclosed in the presentembodiment, in the case in which the dimension of the treatment target Tis small, it is possible for the surgeon to directly perform thetreatment with respect to the treatment target T without confirming theimages acquired by the objective lens 215 of the endoscope 200. In thiscase, it is unnecessary for the surgeon to operate the objective lens215 of the endoscope 200 and the endoscopic treatment device such thatthe surgery becomes simple.

Fourth Embodiment

Hereinafter, a medical stapler 100C according to a fourth embodiment ofthe present disclosure will be described by referring from FIG. 22 toFIG. 24 . The medical stapler 100C according to the present embodimentis different from the medical stapler 100 according to theabove-described first embodiment in the shape of the second graspingmember 22C.

FIG. 22 is a cross-sectional view showing a grasping portion 2C of themedical stapler 100C in the closed state according to the presentembodiment. FIG. 23 is a side view showing the grasping portion 2C ofthe medical stapler 100C in the closed state. FIG. 24 is a partialenlarged view showing the grasping portion 2C of the medical stapler100C in the closed state.

As shown in FIG. 22 and FIG. 23 , the grasping portion 2C includes thefirst grasping member 21C, the second grasping member 22C, theopen-close rotation shaft 23, and the movable pin 27. The first graspingmember 21C and the second grasping member 22C are connected by theopen-close rotation shaft 23 to be openable and closeable.

Compared with the first grasping member 21 according to the firstembodiment, the first grasping member 21C is different in the shape of afirst distal-end portion 21Ca. A first inclination surface 21Cs inclinedwith respect to the central axis O is provided at the distal-end side onthe upper surface 21Ce of the first distal-end portion 21Ca included inthe first grasping member 21C.

Compared with the second grasping member 22 according to the firstembodiment, the second grasping member 22C is different in the shape ofthe second distal-end portion 22Cc and the U-shaped member 22Ca. Asecond inclination surface 22Cs inclined with the central axis O at thedistal-end side is formed in the lower surface 22Ce of the seconddistal-end portion 22Cc included in the second grasping member 22C. TheU-shaped member 22Ca included in the second grasping member 22C includeda concave portion 22Cf at the inside being opposite to the firstgrasping member 21C when the grasping portion 2C is in the closed state.The concave portion 22Cf is recessed toward the outside being oppositeto the inside from the inside thereof.

As shown in FIG. 22 , when the grasping portion 2C is in the closedstate, the first inclination surface 21Cs and the second inclinationsurface 22Cs form a tapered surface Ts widen at the distal-end side.When the surgeon grasps the treatment target T by the grasping portion2C, the treatment target T is grasped along the tapered surface Ts.Accordingly, the grasping portion 2C is configured to definitely graspthe treatment target T and it is difficult for the treatment target T toescape from the grasping portion 2C.

As shown in FIG. 22 , the grasping portion 2C includes the concaveportion 22Cf such that when the surgeon grasps the treatment target Tusing the grasping portion 2C, the space in the grasping portion 2C foraccommodating the treatment target T is wide. The treatment target T ishooked on the second distal-end portion 22Cc in which the staplereception portion 4 is provided so as to prevent the treatment target Tfrom slipping out. Accordingly, the grasping portion 2C can furtherdefinitely grasp the treatment target T to make it difficult for thetreatment target T to escape from the grasping portion 2C.

Hereinafter, the configuration for smoothly performing the treatmentwith respect to the treatment target T by using the medical stapler 100Caccording to the present embodiment will be described based on FIG. 23and FIG. 24 . As shown in FIG. 23 , in the state in which the treatmenttarget T is grasped by the grasping portion 2C, both the repulsive forceby the living tissue as the treatment target T and the force to pull theopen-close operation wire 5 to the proximal-end side are applied to thegrasping portion 2C. That is, the first grasping member 21C and thesecond grasping member 22C of the grasping portion 2C grasp thetreatment target T to be in a substantially stationary state.

As shown in FIG. 24 , an angle formed between the tangent at the contactportion of the first grasping member 21C and the movable pin 27 and thetangent at the contact portion of the second grasping member 22C and themovable pin 27 is defined as a slide angle θ. As shown in FIG. 24 , theforce N1 due to the repulsive force of the living tissues as thetreatment target T and the force N2 due to the force to pull theopen-close operation wire 5 are applied on the movable pin 27. At thistime, due to the balance of the forces, the force N1 is equal to thecomponent force N2*cos θ of the force N2.

When the treatment with respect to the treatment target T using themedical stapler 100C is performed, for example, by pressing theopen-close operation wire 5 to the distal-end side, it is possible torelease the treatment target T that is grasped by the grasping portion2C. On the other hand, for example, at the time of pulling theopen-close operation wire 5 while resisting the repulsive force due tothe treatment target T, it is necessary to prepare for the case in whichthe open-close operation wire 5 is broken due to the excessive forceapplied to the open-close operation wire 5. Accordingly, it ispreferable that the grasping portion 2C can be opened only by therepulsive force of the treatment target T even there is no pressingforce toward the movable pin 27 by the open-close operation wire 5.

According to the present embodiment, as shown in FIG. 24 , due to theoperations of pressing the open-close operation wire 5, the open-closeoperation wire 5 applies the force F to the movable pin 27. Also, thefriction coefficient between the first grasping member 21C and themovable pin 27, and the friction coefficient between the second graspingmember 22C and the movable pin 27 are the same coefficient μ.Accordingly, the movable pin 27 moves toward the distal-end side in theaxial direction A. That is, in order to open the first grasping member21C and the second grasping member 22C of the grasping portion 2C, it isnecessary to satisfy the following equation (1).

F+N ₂*cos θ>μ*N ₁ +μ*N ₂+sin θ  (1)

As described above, the value N1 is equal to the value N2*cos θ suchthat the following equation (2) can be achieved by deforming theabove-described equation (1).

2*μ*N ₂*cos θ−N ₂*sin θ<F  (2)

According to the present embodiment, it is preferable that the graspingportion 2C can be opened only by the repulsive force due to thetreatment target T, that is, even in the case in which the value F iszero, it is preferable that the grasping portion 2C can be opened, thusthe following equation (3) can be achieved.

tan θ>2*μ  (3)

That is, by calculating the slide angle θ based on the frictioncoefficient between the first grasping member 21C and the movable pin27, and the friction coefficient between the second grasping member 22Cand the movable pin 27, it is possible to open the first grasping member21C and the second grasping member 22C of the grasping portion 2C onlyby the repulsive force of the treatment target T without operating theopen-close operation wire 5. According to the present embodiment, forexample, in the case in which the friction coefficient is 0.05, theslide angle may be equal to or larger than 5.7 degrees.

According to the medical stapler 100C disclosed in the presentembodiment, similar to the above-described embodiments, even in thenarrow surgery site such as the gastrointestinal tract or the likeinside the body of the patient, it is possible to smoothly switch theopen state and the closed state of the grasping portion 2C of themedical stapler 100C.

Although the respective embodiments and modifications of the presentdisclosure have been described above, the technical scope of the presentdisclosure is not limited to the above-described embodiments, andconfigurations in the respective embodiments and modifications withinthe scope not departing from the spirit of the present disclosure. It ispossible to change the combination of elements, make various changes toeach configuration element, or delete each configuration element. Forexample, the configuration according to any one of above-describedembodiments and modifications of the present disclosure may beappropriately combined with each modification of the operation section.The present disclosure is not limited by the above description, but onlyby the appended claims.

What is claimed is:
 1. A medical stapler, comprising: a grasping portionconnected to an endoscope and having a first jaw and a second jawconnected by a rotation shaft; an operation portion configured toreceive an external force for operating the grasping portion to open andclose; a first wire including a proximal end connected with theoperation portion and a distal end connected with the grasping portionand configured to transmit the external force that is received by theoperation portion to the grasping portion; and a movable pin attached tothe distal end of the first wire, wherein the grasping portion istransitioned to an open state and a closed state by the first jaw andthe second jaw relatively rotating with the rotation shaft as a rotationcenter due to the external force transmitted by the first wire, therotation shaft is positioned at a distal-end side of a distal end of theendoscope along a longitudinal direction of the endoscope, the movablepin is advanceable and retractable between a position at theproximal-end side of the rotation shaft and a position at the distal-endside of the rotation shaft along the longitudinal direction in a statein which the movable pin is engaged with an engagement groove formed inthe first jaw, a first tangent in a contact portion of the first jaw andthe movable pin and a second tangent in a contact portion of the secondjaw and the movable pin are inclined with each other at a slide angle θ,and the slide angle θ is determined by an equation, wherein the value μis a friction coefficient between the first jaw or the second jaw andthe movable pin.tan θ>2*μ  (3)
 2. The medical stapler according to claim 1, wherein thegrasping portion grasps a treatment target in a state in which the firstjaw and the second jaw are opposite to each other when the graspingportion is in the closed state, and when the grasping portion is in theopen state, the first jaw and the second jaw form an angle substantiallyto be 90 degrees.
 3. The medical stapler according to claim 1, whereinthe first jaw is fixed to the endoscope and includes a staple extractionportion, the second jaw includes a staple reception portion, and thesecond jaw rotates with respect to the first jaw with the rotation shaftas the rotation center.
 4. The medical stapler according to claim 1,wherein the endoscope includes an objective lens provided in thedistal-end portion for observing the treatment target, and a firstdistance between a central axis of the endoscope and the rotation shaftis equal to or larger than a second distance between the central axis ofthe endoscope and a center of the objective lens.
 5. The medical stapleraccording to claim 1, wherein the endoscope includes a treatment channelformed to extend from a distal end to a proximal end thereof forinserting an endoscopic treatment device through the endoscope, thetreatment channel includes an opening at a distal-end portion of theendoscope, and a first distance between a central axis of the endoscopeand the rotation shaft is equal to or larger than a radius of a circlewith the central axis of the endoscope as a center that circumscribesthe opening.
 6. The medical stapler according to claim 1, wherein whenthe grasping portion is in the open state, the second jaw is positionedbetween the rotation shaft and the endoscope in the longitudinaldirection of the endoscope.
 7. The medical stapler according to claim 1,wherein a first region in which the first wire is advanceable andretractable by the operations of the operation portion is formed at anoutside of the rotation shaft in a radial direction of the endoscope. 8.The medical stapler according to claim 7, further comprises a secondwire configured to transmit an external force to the staple extractionportion provided in the first jaw so as to extract a staple, wherein asecond region in which the second wire is advanceable and retractable bythe operations of the operation portion is formed at an inside of thefirst region in the radial direction of the endoscope.
 9. The medicalstapler according to claim 1, wherein when the grasping portion is inthe closed state, a gap having a predetermined distance is formedbetween a distal-end portion of the first jaw and a distal-end portionof the second jaw.
 10. The medical stapler according to claim 1, whereinthe first jaw includes a staple extraction portion fixed to theendoscope, the second jaw includes a staple reception portion, thesecond jaw is provided with a concave portion formed in at least part ofa region in a direction from the staple reception portion to therotation shaft, and a distance between the first jaw to the concaveportion is larger than a distance from the first jaw to other part ofthe second jaw.
 11. A medical system, comprising: an endoscope havingflexibility; and a medical stapler engaged with the endoscope, whereinthe medical stapler comprises: a grasping portion connected to anendoscope and having a first jaw and a second jaw connected by arotation shaft; an operation portion configured to receive an externalforce for operating the grasping portion to open and close; a first wireincluding a proximal end connected with the operation portion and adistal end connected with the grasping portion and configured totransmit the external force that is received by the operation portion tothe grasping portion; and a movable pin attached to the distal end ofthe first wire, wherein the grasping portion is transitioned to an openstate and a closed state by the first jaw and the second jaw relativelyrotating with the rotation shaft as a rotation center due to theexternal force transmitted by the first wire, the rotation shaft ispositioned at a distal-end side of a distal end of the endoscope along alongitudinal direction of the endoscope, the movable pin is advanceableand retractable between a position at the proximal-end side of therotation shaft and a position at the distal-end side of the rotationshaft along the longitudinal direction in a state in which the movablepin is engaged with an engagement groove formed in the first jaw, afirst tangent in a contact portion of the first jaw and the movable pinand a second tangent in a contact portion of the second jaw and themovable pin are inclined with each other at a slide angle θ, and theslide angle θ is determined by an equation, wherein the value μ is afriction coefficient between the first jaw or the second jaw and themovable pin.tan θ>2*μ  (3)
 12. The medical system according to claim 11, wherein thegrasping portion grasps a treatment target in a state in which the firstjaw and the second jaw are opposite to each other when the graspingportion is in the closed state, and when the grasping portion is in theopen state, the first jaw and the second jaw form an angle substantiallyto be 90 degrees.
 13. The medical system according to claim 11, whereinthe first jaw is fixed to the endoscope and includes a staple extractionportion, the second jaw includes a staple reception portion, and thesecond jaw rotates with respect to the first jaw with the rotation shaftas the rotation center.
 14. The medical system according to claim 11,wherein the endoscope includes an objective lens provided in thedistal-end portion for observing the treatment target, and a firstdistance between a central axis of the endoscope and the rotation shaftis equal to or larger than a second distance between the central axis ofthe endoscope and a center of the objective lens.
 15. The medical systemaccording to claim 11, wherein the endoscope includes a treatmentchannel formed to extend from a distal end to a proximal end thereof forinserting an endoscopic treatment device through the endoscope, thetreatment channel includes an opening at a distal-end portion of theendoscope, and a first distance between a central axis of the endoscopeand the rotation shaft is equal to or larger than a radius of a circlewith the central axis of the endoscope as a center that circumscribesthe opening.
 16. The medical system according to claim 11, wherein whenthe grasping portion is in the open state, the second jaw is positionedbetween the rotation shaft and the endoscope in the longitudinaldirection of the endoscope.
 17. The medical system according to claim11, wherein a first region in which the first wire is advanceable andretractable along the longitudinal direction is formed at an outside ofthe rotation shaft in a radial direction of the endoscope.
 18. Themedical system according to claim 17, wherein the medical staplerfurther comprises a second wire configured to transmit an external forceto the staple extraction portion provided in the first jaw so as toextract a staple, and a second region in which the second wire isadvanceable and retractable along the longitudinal direction is formedat an inside of the first region in the radial direction of theendoscope.
 19. The medical system according to claim 11, wherein whenthe grasping portion is in the closed state, a gap having apredetermined distance is formed between a distal-end portion of thefirst jaw and a distal-end portion of the second jaw.
 20. The medicalsystem according to claim 11, wherein the first jaw includes a stapleextraction portion fixed to the endoscope, the second jaw includes astaple reception portion, the second jaw is provided with a concaveportion formed in at least part of a region in a direction from thestaple reception portion to the rotation shaft, and a distance betweenthe first jaw to the concave portion is larger than a distance from thefirst jaw to other part of the second jaw.